[Feature Request] Expose HalfSerializer for public use?

[jeffijoe]

I recently had a case where I was building an observable wrapper over a module where OnNext would be guaranteed to be called serially, while OnCompleted/OnError may be called concurrently.

Since I knew OnCompleted/OnError would not be called frequently, I used a SpinLock where the OnNext path would use TryEnter (non-blocking) and the OnComplete/OnError would use Enter (spin-waiting), and this works fine given my situation.

I later went digging through the Rx.NET source and found this absolute gem by the name of HalfSerializer which is exactly what I needed for my use case! The implementation is very elegant and completely non-blocking. 🤩

Would it be possible to expose a thin wrapper around it that allows me to pass in an IObserver<T> rather than ISink<T>?